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cmlibs / zinc

Source code repository for OpenCMISS-Zinc
Mozilla Public License 2.0
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Markers with fixed size in window coordinates #259

Open rchristie opened 1 year ago

rchristie commented 1 year ago

Want to have markers located in world or local coordinates but with fixed sizes in window coordinates. Use case is "teardrop" indicators for small data.

Plan:

  1. Set graphics to have a window scene transformation (not local/world), which will make graphics shown as overlay and all fields interpreted in that coordinate system by default.
  2. Have graphics point attributes transformation for coordinates and orientation scale field: NONE, FROM_LOCAL, FROM_WORLD.
  3. If either of the above transformations are in use, graphics vertex buffer is regenerated before every redraw so transformation is made for the current Sceneviewer.
  4. Optional: support non-overlay markers in window coordinates, so they are fixed size but are subject to the depth buffer and translucency along with local/world graphics. This will need another graphics option to change default behaviour.